Global navigation satellite system

ABSTRACT

Each of a first and a second navigation satellite system (NSS) are adapted to operate according to a first and a second specification, respectively, and each includes a first and a second plurality of satellite vehicles (SV), respectively. Each of the first and the second plurality of SVs are adapted to be identified by a first and a second plurality of unique corresponding identifications (IDs), respectively. A processor is adapted to receive and identify a first plurality of corresponding signals transmitted from the first plurality of SVs in response to the first plurality of unique corresponding IDs. The processor is adapted to receive and identify a second plurality of corresponding signals transmitted from the second plurality of SVs in response to the second plurality of unique corresponding IDs. The processor is adapted to determine position location information in response to receiving and identifying the first plurality of corresponding signals and the second plurality of corresponding signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 60/758,244, filed on Jan. 10, 2006 entitled, “Evaluation of VariousOptions for the Introduction of GNSS” and to U.S. ProvisionalApplication No. 60/782,955, filed on Mar. 15, 2006 entitled, “VirtualGNSS Time,” both of which are assigned to the assignee hereof and areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to communication systems. Moreparticularly, the present invention relates to a communication systemincluding a global navigation satellite system.

BACKGROUND OF THE INVENTION

There are many different types of technologies employed in calculatingthe location of mobile stations in wireless networks with various levelsof success and accuracy. Assisted-GPS (A-GPS) is a positioningtechnology that is presently used for locating mobile stations inwireless networks. An A-GPS server provides assistance data to themobile station in order for it to have a low Time to First Fix (TTFF),to permit weak signal acquisition, and to optimize mobile stationbattery use. A-GPS is used as a location technology in isolation orhybridized with other positioning technologies that provide range-likemeasurements.

An A-GPS server provides data to a wireless mobile station that isspecific to the approximate location of a mobile station. The assistancedata helps the mobile station lock onto satellites quickly, andpotentially allows the handset to lock onto weak signals. The mobilestation then performs the position calculation or optionally returns themeasured code phases to the server to do the calculation. The A-GPSserver can make use of additional information such as round-trip timingmeasurements from a cellular base station to the mobile station in orderto calculate a location where it may otherwise not be possible, forexample when there are not enough GPS satellites visible.

Advances in satellite-based global positioning system (GPS), timingadvance (TA), and terrestrial-based enhanced observed time difference(E-OTD) position fixing technology enable a precise determination of thegeographic position (e.g., latitude and longitude) of a mobile stationsubscriber. As geographic location services are deployed within wirelesscommunications networks, such positional information may be stored innetwork elements and delivered to nodes in the network using signalingmessages. Such information may be stored in SMLCs (Serving MobileLocation Centers), SASs (Stand-Alone SMLCs), PDEs (Position DeterminingEntities), SLPs (Secure User Plane Location Location Platforms) andspecial purpose mobile subscriber location databases.

One example of a special purpose mobile subscriber location database isthe SMLC proposed by the 3rd Generation Partnership Project (3GPP). Inparticular, 3GPP has defined a signaling protocol for communicatingmobile subscriber positional information to and from an SMLC. Thissignaling protocol is referred to as the Radio Resource LCS (LocationServices) protocol, denoted RRLP, and defines signaling messagescommunicated between a mobile station and an SMLC related to a mobilesubscriber's location. A detailed description of the RRLP protocol isfound in 3GPP TS 44.031 v7.2.0 (2005-11)3^(rd) Generation PartnershipProject; Technical Specification Group GSM Edge Radio Access Network;Location Services (LCS); Mobile Station (MS)—Serving Mobile LocationCenter (SMLC) Radio Resource LCS Protocol (RRLP) (Release 7).

In addition to the United States Global Positioning System (GPS), otherSatellite Positioning Systems (SPS), such as the Russian GLONASS systemor the proposed European Galileo System may also be used for positionlocation of a mobile station. However, each of the systems operatesaccording to different specifications.

Accordingly, there is a need for a communication system, including aglobal navigation satellite system (GNSS), which can determine aposition location for a mobile station based on satellite signals sentfrom two or more satellite systems, rather than just one satellitesystem, to provide further efficiencies and advantages for positionlocation.

SUMMARY OF THE INVENTION

The present invention includes a method, an apparatus, and/or a system.The apparatus may include data processing systems, which perform themethod, and computer readable media storing executable applicationswhich, when executed on the data processing systems, cause the dataprocessing systems to perform the method.

According to one aspect of the present invention, each of a first and asecond global navigation satellite system (GNSS) are adapted to operateaccording to a first and a second specification, respectively, and eachincludes a first and a second plurality of satellite vehicles (SV),respectively. Each of the first and the second plurality of SVs areadapted to be identified by a first and a second plurality of uniquecorresponding identifications (IDs), respectively. A processor isadapted to receive and identify a first plurality of correspondingsignals transmitted from the first plurality of SVs in response to thefirst plurality of unique corresponding IDs. The processor is adapted toreceive and identify a second plurality of corresponding signalstransmitted from the second plurality of SVs in response to the secondplurality of unique corresponding IDs. The processor is adapted todetermine position location information in response to receiving andidentifying the first plurality of corresponding signals and the secondplurality of corresponding signals.

According to other aspects of the present invention, the presentinvention employs an apparatus, a method, a computer readable memory,and a signal protocol.

These and other aspects of the present invention will be apparent fromthe accompanying drawings and from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present invention are illustrated by way of examples andnot limitation in the figures of the accompanying drawings, in whichlike reference numbers designate corresponding elements.

FIG. 1 illustrates a block diagram representation of a communicationsystem, including a global navigation satellite system (GNSS), acellular system, and a mobile station, according to one aspect of thepresent invention.

FIG. 2 illustrates Table A representing four options for modifying aradio resource location services protocol (RRLP) position measurerequest message and a RRLP position measure response message for apresent RRLP specification, according to one aspect of the presentinvention.

FIG. 3 illustrates a method for modifying the present RRLP positionmeasure request message and present RRLP position measure responsemessage in accordance with one of the four options, according to oneaspect of the present invention.

FIG. 4 illustrates Table 1 representing the RRLP position measurerequest message for the present RRLP specification, according to oneaspect of the present invention.

FIG. 5 illustrates Table 2 representing the RRLP position measureresponse message for a present RRLP specification, according to oneaspect of the present invention.

FIGS. 6 and 7 illustrate Table 3 representing a modified RRLP positionmeasure request message in accordance with option one, according to oneaspect of the present invention.

FIGS. 8 and 9 illustrate Table 4 representing a modified RRLP positionmeasure response message in accordance with option one, according to oneaspect of the present invention.

FIGS. 10 and 11 illustrate Table 5 representing a modified RRLP positionmeasure request message in accordance with option two, according to oneaspect of the present invention.

FIGS. 12 and 13 illustrate Table 6 representing a RRLP position measureresponse message in accordance with option two, according to one aspectof the present invention.

FIG. 14 illustrates Table 7 representing a modified RRLP positionmeasure request message in accordance with option three, according toone aspect of the present invention.

FIGS. 15 and 16 illustrate Table 8 representing a RRLP position measureresponse message in accordance with option three, according to oneaspect of the present invention.

FIGS. 17 and 18 illustrate Table 9 representing a RRLP position measurerequest message in accordance with option four, according to one aspectof the present invention.

FIGS. 19 and 20 illustrate Table 10 representing a RRLP position measureresponse message in accordance with option four, according to one aspectof the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following description and drawings are illustrative of the inventionand are not to be construed as limiting the invention. Numerous specificdetails are described to provide a thorough understanding of the presentinvention. However, in certain instances, well-known or conventionaldetails are not described in order to avoid obscuring the description ofthe present invention. References to one embodiment or an embodiment inthe present disclosure are not necessarily to the same embodiment, andsuch references include one or more embodiments.

Communication System 10

FIG. 1 illustrates a block diagram representation of a communicationsystem 10, including a global navigation satellite system (GNSS) 11, acellular system 12, a landline telephone system 13, according to oneaspect of the present invention. The GNSS system 11 includes multipleglobal navigation satellites 14-21, including a first set of satellites14-17 associated with a first GNSS and a second set of satellites 18-21associated with a second GNSS. The first and second GNSS may be any twodifferent GNSS, for example, the United States Global Positioning System(GPS) or other Satellite Positioning System (SPS), such as the RussianGLONASS system, or the proposed European Galileo System.

The cellular system 12 includes multiple cellular base stations 22-24(“base station”), a mobile switching center 25, and a location server,which is otherwise called a position determining entity (PDE) 26. PDE 26may be a 3GPP SMLC or 3GPP SAS. Each base station 22-24 further includesa base station (BS) transmitter 27, a BS receiver 28, a GPS receiver 29,and a first GNSS receiver (e.g., a GPS receiver) 29, and a second GNSSreceiver (e.g., Galileo receiver) 30. The first and second GNSSreceivers may be located inside or outside the base stations 22-24. TheGPS receiver 29 receives signals from the GPS satellites 14-17. TheGalileo receiver 35 receives signals from the Galileo satellites 18-21.

The communication system 10 provides wireless communications for themobile station 31, and is not limited to cellular, fixed wireless, PCS,or satellite communications systems. The communication system 10 mayprovide for multiple access communications, in accordance with anystandard or protocol, such as, for example, CDMA, TDMA, FDMA, or GSM, orcombinations thereof.

Global Navigation Satellite System (GNSS) 11

The GNSS system 11 is a collection of satellites, such as GPS satellites14-17 and Galileo satellites 18-21, each of which travels in apredictable orbit above the earth's surface. Each satellite transmits asignal modulated with a pseudo-noise (PN) code unique to the satellite.Each PN code comprises a predetermined number of chips. For example forGPS, the PN code is a sequence of 1,023 chips that is repeated everymillisecond. A GPS receiver, such as GPS receiver 24, receives acomposite signal comprising a mixture of signals from each of thesatellites that are visible to the GPS receiver. A signal detector inthe receiver detects a transmission from a particular satellite bydetermining the degree of correlation between the received signal andshifted versions of the PN code for that satellite. If a peak ofsufficient quality in the correlation value for one of the shift offsetsis detected, the GPS receiver is considered to have detected thetransmission from the satellite.

To perform position location for the mobile station 31 in wirelesscellular networks (e.g., cellular system 12), several approaches, forexample, to perform a position calculation using a number ofgeometrically distinct measurements, such as range, pseudorange, roundtrip delay and others that are associated with distinct reference points(e.g., GPS satellites, pseudolites, base stations, surface of theearth).

One approach, called Advanced Forward Link Trilateration (AFLT) orEnhanced Observed Time Difference (E-OTD), measures at the mobilestation 31 the times of arrival of signals transmitted from each ofseveral base stations (e.g., transmissions from base stations 22-24).These times are transmitted to a Position Determination Entity (PDE)(e.g., a location server) 26, which computes the position of the mobilestation 31 using these times of reception. The transmit times at thesebase stations are coordinated such that at a particular instance oftime, the times-of-day associated with multiple base stations 22-24 arewithin a specified error bound. The accurate positions of the basestations 22-24 and the times of reception are used to determining theposition of the mobile station 31.

In an AFLT system, the times of reception of signals from the basestations 22-24 are measured at the mobile station 31. This timing datamay then be used to compute the position of the mobile station 31. Suchcomputation may be done at the mobile station 31 or at the locationserver 26, if the timing information so obtained by the mobile station31 is transmitted to the location server 26 via a communication link.Typically, the times of receptions are communicated to the locationserver 26 through one of the cellular base stations 22-24. The locationserver 26 is coupled to receive data from the base stations through themobile switching center 25. The location server 26 may include a basestation almanac (BSA) server, which provides the location of the basestations and/or the coverage area of base stations. Alternatively, thelocation server 26 and the BSA server may be separate from each other,and the location server 26 communicates with the base station to obtainthe base station almanac for position determination. The mobileswitching center 25 provides signals (e.g., voice, data, and/or videocommunications) to and from the landline Public Switched TelephoneSystem (PSTS) 13 so that signals may be conveyed to and from the mobilestation 31 to other telephones (e.g., landline phones on the PSTS orother mobile telephones). In some cases, the location server 26 may alsocommunicate with the mobile switching center 25 via a cellular link. Thelocation server 26 may also monitor emissions from several of the basestations 22-24 in an effort to determine the relative timing of theseemissions.

In another approach, called Time Difference of Arrival (TDOA), the timesof reception of a signal from the mobile station 31 is measured atseveral base stations 22-24. This timing data may then be communicatedto the location server 26 to compute the position of the mobile station31.

Yet a third approach of doing position location involves the use in themobile station 31 of a receiver for the United States Global PositioningSystem (GPS) or other Satellite Positioning System (SPS), such as theRussian GLONASS system or the proposed European Galileo System. TheGLONASS system primarily differs from GPS system in that the emissionsfrom different satellites are differentiated from one another byutilizing slightly different carrier frequencies, rather than utilizingdifferent pseudorandom codes. In this situation, and with the Galileosystem, substantially all the circuitry and algorithms describedpreviously are applicable. The term “GNSS” used herein includes suchalternative satellite positioning systems, including the Russian GLONASSsystem and the proposed European Galileo System.

In the third approach, the GPS receiver 34 estimates its location bydetecting transmissions from some of the satellites 14-17. For eachdetected transmission, the receiver uses the shift in the PN code toestimate the delay (in terms of chips or fractions of chips) betweentime of transmission and time of arrival. Given the known propagationspeed of the positioning signal, the GPS receiver estimates the distancebetween itself and the satellite. This estimated distance defines asphere around the satellite. The GPS receiver 34 knows the preciseorbits and positions of each of the satellites, and continuouslyreceives updates to these orbits and positions. From this information,the GPS receiver 34 is able to determine its position (and the currenttime) from the point where the spheres for the four satellitesintersect. In combination with or as alternative to the GPS receiver 34,the Galileo receiver 35 may estimate its location by detectingtransmissions from at least four of the satellites 18-21.

Although the methods and apparatus of the present invention have beendescribed with reference to GPS satellites, it will be appreciated thatthe description are equally applicable to positioning systems whichutilize pseudolites, or a combination of satellites and pseudolites.Pseudolites are ground-based transmitters, which broadcast a PN code(similar to a GPS signal) modulated on an L-band carrier signal,generally synchronized with GPS time. Each transmitter may be assigned aunique PN code to permit identification by a remote receiver.Pseudolites are useful in situations where GPS signals from an orbitingsatellite might be unavailable, such as tunnels, mines, buildings, orother enclosed areas. The term “satellite”, as used herein, is intendedto include pseudolites or equivalents of pseudolites, and the term GPSsignals, as used herein, are intended to include GPS-like signals frompseudolites or equivalents of pseudolites.

Such a method using a receiver for satellite positioning signals (SPS)signals may be completely autonomous or may utilize the cellular networkto provide assistance data or to share in the position calculation. Asshorthand, these various methods are referred to as “GPS.” Examples ofsuch methods are described in U.S. Pat. Nos. 5,945,944; 5,874,914;6,208,290; 5,812,087; and 5,841,396.

For instance, U.S. Pat. No. 5,945,944 describes a method to obtain fromcellular phone transmission signals accurate time information, which isused in combination with GPS signals to determine the position of thereceiver. U.S. Pat. No. 5,874,914 describes a method to transmit theDoppler frequency shifts of in view satellites to the receiver through acommunication link to determine the position of the receiver. U.S. Pat.No. 5,874,914 further describes a method to transmit satellite almanacdata (or ephemeris data) to a receiver through a communication link tohelp the receiver to determine its position. U.S. Pat. No. 5,874,914also describes a method to lock to a precision carrier frequency signalof a cellular telephone system to provide a reference signal at thereceiver for GPS signal acquisition. U.S. Pat. No. 6,208,290 describes amethod to use an approximate location of a receiver to determine anapproximate Doppler for reducing SPS signal processing time. U.S. Pat.No. 5,812,087 describes a method to compare different records of asatellite data message received at different entities to determine atime at which one of the records is received at a receiver in order todetermine the position of the receiver.

In practical low-cost implementations, both the MS receiver 33, the GPSreceiver 34, and/or the Galileo receiver 35 are integrated into the sameenclosure and, may in fact share common electronic circuitry, such asreceiver circuitry and/or antenna.

In yet another variation of the above methods, the round trip delay(RTD) is found for signals that are sent from the base station 22, 23,or 24 to the mobile station 31 and then are returned to thecorresponding base station 22, 23, or 24. In a similar but alternativemethod, the round trip delay is found for signals that are sent from themobile station 31 to the base station and then returned to the mobilestation 31. The round-trip delays are each divided by two to determinean estimate of the one-way time delay. Knowledge of the location of thebase station, plus a one-way delay constrains the location of the mobilestation 31 to a circle on the earth. Two such measurements from distinctbase stations then result in the intersection of two circles, which inturn constrains the location to two points on the earth. A thirdmeasurement (even an angle of arrival or cell sector) resolves theambiguity.

A combination of another position method such as AFLT or TDOA with a GPSsystem is called a “hybrid” system. For example, U.S. Pat. No. 5,999,124describes a hybrid system, in which the position of a cell basedtransceiver is determined from a combination of at least: i) a timemeasurement that represents a time of travel of a message in the cellbased communication signals between the cell based transceiver and acommunication system, and ii) a time measurement that represents a timeof travel of an SPS signal.

Altitude aiding has been used in various methods for determining theposition of a mobile device. Altitude aiding is typically based on apseudo-measurement of the altitude. The knowledge of the altitude of alocation of a mobile station 31 constrains the possible positions of themobile station 31 to a surface of a sphere (or an ellipsoid) with itscenter located at the center of the earth. This knowledge may be used toreduce the number of independent measurements required to determine theposition of the mobile station 31. For example, U.S. Pat. No. 6,061,018describes a method where an estimated altitude is determined from theinformation of a cell object, which may be a cell site that has a cellsite transmitter in communication with the mobile station 31.

When a minimum set of measurements are available, a unique solution tothe navigation equations can be determined for the position of themobile station 31. When more than one extra measurement is available,the “best” solution may be obtained to best fit all the availablemeasurements (e.g., through a least square solution procedure thatminimizes the residual vector of the navigation equations). Since theresidual vector is typically non-zero when there are redundantmeasurements, due to the noises or errors in the measurements, anintegrity-monitoring algorithm can be used to determine if all themeasurements are consistent with each other.

For example, a traditional Receiver Autonomous Integrity Monitoring(RAIM) algorithm may be used to detect if there is a consistency problemin the set of the redundant measurements. For example, one RAIMalgorithm determines if the magnitude of the residual vector for thenavigation equations is below a threshold value. If the magnitude of theresidual vector is smaller than the threshold, the measurements areconsidered consistent. If the magnitude of the residual vector is largerthan the threshold, there is an integrity problem, in which case one ofthe redundant measurements that appears to cause the most inconsistencymay then be removed to obtain an improved solution.

Cellular System 12

Multiple cellular base stations 22-24 are typically arranged to cover ageographical area with radio coverage, and these different base stations22-24 are coupled to at least one mobile switching center 25, as is wellknown in the prior art. Thus, multiple base stations 22-24 would begeographically distributed, but coupled by a mobile switching center 25.The cellular system 12 may be connected to a network of reference GPSreceivers 29, which provide differential GPS information, and mayprovide GPS ephemeris data for use in calculating the position of mobilestations. The cellular system 12 may be connected to a network ofreference Galileo receivers 30, which provide differential Galileoinformation, and may provide Galileo ephemeris data for use incalculating the position of mobile stations. The cellular system 12 iscoupled through a modem or other communication interface, to othercomputers or network components, and/or to computer systems operated byemergency operators, such as the Public Safety Answering Points, whichrespond to 911 telephone calls. In IS-95 compliant CDMA systems, eachbase station or sector 22-24 transmits a pilot signal, which ismodulated with a repeating pseudo-random noise (PN) code, which uniquelyidentifies that base station. For example, for IS-95 compliant CDMAsystems, the PN code is a sequence of 32,768 chips, which is repeatedevery 26.67 mSec.

The location server 26 typically includes communication devices, such asmodems or network interface. The location server 26 may be coupled to anumber of different networks through communication devices (e.g., modemsor other network interfaces). Such networks include the mobile switchingcenter 25 or multiple mobile switching centers, land based phone systemswitches, cellular base stations 22-24, other GPS signal receivers,other Galileo receiver, or other processors or location servers. Variousexamples of methods for using a location server 26 have been describedin numerous U.S. Patents, including: U.S. Pat. Nos. 5,841,396,5,874,914, 5,812,087, and 6,215,442.

The location server 26, which is a form of a data processing system,includes a bus, which is coupled to a microprocessor and a ROM andvolatile RAM and a non-volatile memory (each not shown). The processoris coupled to cache memory (not shown). The bus interconnects thesevarious components together. The location server 26 may utilize anon-volatile memory, which is remote from the cellular system 12, suchas a network storage device, which is coupled to the data processingsystem through a network interface such as a modem or Ethernetinterface. The bus may include one or more buses connected to each otherthrough various bridges, controllers and/or adapters as are well knownin the art. In many situations, the location server 26 may perform itsoperations automatically without human assistance. In some designs wherehuman interaction is required, an I/O controller (not shown) maycommunicate with displays, keyboards, and other I/O devices. It willalso be appreciated that network computers and other data processingsystems which have fewer components or perhaps more components may alsobe used with the present invention and may act as a location server or aPDE.

Mobile Station 31

A cellular mobile station 31 (“mobile station”) includes a first GNSSreceiver (e.g., a GPS receiver) 34, and a second GNSS receiver (e.g.,Galileo receiver) 35, a mobile station (MS) transmitter 32, and a mobilestation receiver 33. The GPS receiver 34 receives signals from the GPSsatellites 14-17. The Galileo receiver 35 receives signals from theGalileo satellites 18-21. The MS transmitter 32 transmits communicationsignals to the BS receiver 28. The MS receiver 33 receives communicationsignals from the BS transmitter 27.

Other elements of the mobile station 31, which are not shown in FIG. 1,include, for example, a GPS antenna, a Galileo antenna, a cellularantenna, a processor, a user interface, a portable power supply, and amemory device. The processor further includes a processor port and othermobile functions.

In the mobile station 31, each satellite signal receiving antenna andsatellite signal receiver includes circuitry, such as acquisition andtracking circuitry (not shown), for performing the functions requiredfor receiving and processing satellite signals. Satellite signals (e.g.,a signal transmitted from one or more satellites 14-17, and/or 18-21)are received through the satellite antenna and input to acquisition andtracking circuit, which acquires the PN (Pseudorandom Noise) codes forthe various received satellites. Data produced by circuit (e.g.,correlation indicators (not shown)) are processed by the processor,either alone or in combination with other data received from orprocessed by the cellular system 12, to produce position location data(e.g., latitude, longitude, time, satellites, etc.)

The cellular antenna and a cellular transceiver (e.g., MS transmitter 32and MS receiver 33) includes circuitry for performing functions requiredfor processing communication signals received and transmitted over acommunication link. The communication link is typically a radiofrequency communication link to another component, such as one or morebase stations 22-24 having communication antenna (not shown).

The cellular transceiver contains a transmit/receive switch (not shown),which routes communication signals (e.g., radio frequency signals) toand from the communication antenna and the cellular transceiver. In somemobile stations, a band splitting filter, or “duplexer,” is used insteadof the T/R switch. Received communication signals are input to acommunication receiver in the cellular transceiver, and passed to aprocessor for processing. Communication signals to be transmitted fromprocessor are propagated to a modulator and frequency converter (notshown), each in the transceiver. A power amplifier (not shown) in thecellular transceiver increases the gain of the signal to an appropriatelevel for transmission to one or more base stations 22-24.

In one embodiment of the mobile station 31, data generated byacquisition and tracking circuitry in the GPS receiver 24 and/or Galileoreceiver 35 is transmitted over a communication link (e.g., a cellularchannel) to one or more base stations 22-24. The location server 26 thendetermines the location of mobile station 31 based on the data from oneor more satellite receivers 34 and 35, the time at which the data weremeasured, and ephemeris data received from the base station's ownsatellite receiver or other sources of such data. The position locationdata can then be transmitted back to mobile station 31 or to otherremote locations. More details about portable receivers utilizing acommunication link are disclosed in commonly assigned U.S. Pat. No.5,874,914.

The mobile station 31 may contain a user interface (not shown), whichmay further provide a data input device and a data output device (eachnot shown).

The data input device typically provides data to a processor in responseto receiving input data either manually from a user or automaticallyfrom another electronic device. For manual input, the data input deviceis a keyboard and a mouse, but also may be a touch screen, or amicrophone and a voice recognition application, for example.

The data output device typically provides data from a processor for useby a user or another electronic device. For output to a user, the dataoutput device is a display that generates one or more display images inresponse to receiving the display signals from the processor, but alsomay be a speaker or a printer, for example. Examples of display imagesinclude, for example, text, graphics, video, photos, images, graphs,charts, forms, etc.

The mobile station 31 may also contain a memory device (not shown)representing any type of data storage device, such as computer memorydevices or other tangible or computer-readable storage medium, forexample. The memory device represents one or more memory devices,located at one or more locations, and implemented as one or moretechnologies, depending on the particular implementation of the mobilestation. In addition, the memory device may be any device readable by aprocessor and capable of storing data and/or a series of instructionsembodying a process. Examples of the memory device include, but are notlimited to, RAM, ROM, EPROM, EEPROM, PROM, disk (hard or floppy),CD-ROM, DVD, flash memory, etc.

The mobile station 31 may contain a processor (not shown) controllingthe operation of the mobile station 31. The other mobile functions inthe processor represent any or all other functions of the mobile station31 that have not already been described herein. Such other mobilefunctions include, for example, operating the mobile station 31 topermit the mobile station to make telephone calls and communicate data.

The mobile station 31 may contain a portable power supply (not shown),which stores and provides portable electrical energy for the electricalelements of the mobile station 31. Examples of the portable power supplyinclude, but are not limited to, batteries and fuel cells. The portablepower supply may be or may not be rechargeable. The portable powersupply typically has a limited amount of stored electrical energy, andneeds to be replaced or renewed after some amount of use so that themobile station can continue to operate.

The mobile station 31 may be fixed (i.e., stationary) and/or mobile(i.e., portable). The mobile station 31 may be implemented in a varietyof forms including, but not limited to, one or more of the following: apersonal computer (PC), a desktop computer, a laptop computer, aworkstation, a minicomputer, a mainframe, a supercomputer, anetwork-based device, a data processor, a personal digital assistant(PDA), a smart card, a cellular telephone, a pager, and a wristwatch.

Position Location Applications

Examples of position location applications include an endless variety ofapplications on land, sea, and air. The scientific community uses GPSfor its precision timing capability and position information. Surveyorsuse GPS for an increasing portion of their work. Recreational uses ofposition location are almost as varied as the number of recreationalsports available. Position location is popular among hikers, hunters,mountain bikers, and cross-country skiers, just to name a few. Anyonewho needs to keep track of where he or she is, to find his or her way toa specified location, or know what direction and how fast he or she isgoing can utilize the benefits of the global positioning system.Position location is now commonplace in vehicles as well. Some basicsystems are in place and provide emergency roadside assistance at thepush of a button (e.g., by transmitting your current position to adispatch center). More sophisticated systems also show the vehicle'sposition on a street map. Currently these systems allow a driver to keeptrack of where he or she is and suggest the best route to follow toreach a designated location.

Position location is useful for determining the location of cellularphones in an emergency and for location based services. Deployment ofcellular position location in the United States is the result of theFederal Communications Commissions' (FCC) Enhanced 9-1-1 mandate. Thatmandate requires that for network-based solutions: 100 meters accuracyfor 67 percent of calls, 300 meters accuracy for 95 percent of calls;for handset-based solutions: 50 meters for 67 percent of calls, 150meters for 95 percent of calls. When an emergency call is initiated, anemergency services coordination center—Public Safety Answering Point(PSAP) will make use of the location that is calculated in the MLC. InEurope and Asia deployment is being driven by Location Based Services(LBS), though requirements for emergency service cellular location havebeen or are being established in these regions.

Global Navigation Satellite System (GNSS)

Assisted—GNSS (A-GNSS), otherwise called “expanded” or “extended” GNSS(E-GNSS), extends the concept to other satellite navigation systemsbesides GPS. For example, there may be eighty GNSS satellites orbitingthe planet within ten years, including GPS, GLONASS, Galileo, and othersatellites, all transmitting a variety of signals based on differentstandards for each system. This will give a receiver (e.g., eithermobile or fixed) access to many more satellites and their transmittingsignals, which can improve both accuracy and yield of position locationdeterminations. More satellites means that position accuracy is lesssusceptible to satellite geometry and provides greater redundancy whendoing the position calculation.

A simplified GNSS architecture is shown in FIG. 1. A cellular system 12,or other type of wide area reference network (WARN) is a network of GNSSreceivers that are placed geographically over the coverage area of thewireless network. The cellular system 12 collects the broadcastnavigation message from the GNSS satellites, and provides it to anA-GNSS server (e.g., PDE 26) for caching. A mobile station 31 makes anemergency call or a service is invoked that requires location and amessage is sent to the A-GNSS server. The PDE 26 calculates the GNSSassistance data required using the location of one or more base stations22-24, as the approximate location and provides it to the mobile station31.

Standards

The different components of an A-GPS server are defined in 3GPP TS23.271, TS 43.059 and TS 25.305. A Serving Mobile Location Center (SMLC)is deployed as part of a wireless network and its purpose is todetermine the location of handsets within the network.

The SMLC runs in GSM/GPRS networks and is known as a Standalone SMLC(SAS) in UMTS networks or a SUPL Location Platform (SLP) when supportingdifferent wireless access types with a user plane solution. The SMLC maysupport all handset-based and network-based wireless position locationmethods, including A-GPS in both handset-based and handset-assistedversions.

There are several different specifications (i.e., standards) supportingprotocols for the A-GPS messaging with the handsets. GSM networks usethe RRLP specification. UMTS networks use the Radio Resource Control(RRC) specification. CDMA networks use the TIA IS-801 and 3GPP2 C.S0022specifications. Each of these specifications specifies different ways ofencoding the same basic information, but is specific to the radiotechnology employed. Although the present description describes examples(i.e., options) for modifying the RRLP specification, the RRCspecification, the IS-801 and C.S0022 specifications or any otherspecification may be modified to achieve the same or similar effects.

The RRLP specification includes a measure position request message 36(FIG. 1), which provides positioning instructions and possiblyassistance data to the mobile station 31, and a measure positionresponse message 37 (FIG. 1), which provides the mobile station 31location estimate or pseudo-range measurements from the mobile station31 to the cellular system 12. The RRC specification, the IS-801/C.S0022specification or any other specification may include request and/orresponse messages to achieve the same or similar effects.

Four Options For Modifying A RRLP Position Measure Message

FIG. 2 illustrates Table A representing four options for modifying theRRLP position measure request message 36 (see FIG. 1) and the RRLPposition measure response message 37 (see FIG. 1) for the RRLPspecification, according to one aspect of the present invention. InTable A, the RRLP position measure request message 36 and the RRLPposition measure response message 37 are represented in the present RRLPspecification in Tables 1 and 2, respectively. Option 1 provides amodified RRLP position measure request message and a modified RRLPposition measure response message in Tables 3 and 4, respectively.Option 2 provides a modified RRLP position measure request message and amodified RRLP position measure response message in Tables 5 and 6,respectively. Option 3 provides a modified RRLP position measure requestmessage and a modified RRLP position measure response message in Tables7 and 8, respectively. Option 4 provides a modified RRLP positionmeasure request message and a modified RRLP position measure responsemessage in Tables 9 and 10, respectively.

Option 1 introduces Galileo/GNSS, as a new satellite location method.

Option 2 introduces a “GNSS location method” and encapsulate the detailsof the various constellations (GPS, Galileo, and potential futuresatellite navigation or augmentation systems) in new GNSS informationelements.

Option 3 introduces a “GNSS location method” independent of anyInterface Control Document (ICD) of the particular constellation.

Option 4 introduces a combination of advantages of Options 2 and 3,after evaluating and comparing each of Options 1, 2, and 3.

Options 1, 2, and 3 have been described for how Galileo/GNSS could beadded to the RRLP specification.

Method for Modifying Measure Position Request and Response Messages

FIG. 3 illustrates a method 38 for modifying the RRLP position measurerequest message 36 and the RRLP position measure response message 37 forthe present RRLP specification in accordance with one of the fouroptions, according to one aspect of the present invention. At block 50the method 38 starts. At block 51, the method 38 identifies the RRLPmeasure position request message 36 (e.g., Table 1). At block 52, themethod 38 modifies the RRLP measure position request message 36 (e.g.,Table 1) according to Option 1 (e.g., Table 3), Option 2 (e.g., Table5), Option 3 (e.g., Table 7), or Option 4 (e.g., Table 9). At block 53,the method 38 identifies the RRLP measure position response message 37(e.g., Table 2). At block 54, the method 38 modifies the RRLP measureposition response message 37 (e.g., Table 2) according to Option 1(e.g., Table 4), Option 2 (e.g., Table 6), Option 3 (e.g., Table 8), orOption 4 (e.g., Table 10).

Each of tables 3, 5, 7, and 9 represent a modified RRLP measure positionrequest message for options 1, 2, 3, and 4, respectively, and includesthe elements of the present RRLP measure position request message, shownin Table 1, as well as new elements 60 to support a second GNSS system(e.g., Galileo). Each of tables 4, 6, 8, and 10 represent a modifiedRRLP measure position response message for options 1, 2, 3, and 4,respectively, and includes the elements of the present RRLP measureposition response message shown in Table 2, as well as new elements 60for the GNSS system (e.g., Galileo). Reference number 60 generallyidentifies the new elements in each of Tables 3-10, although the newelements in each of those tables may be different. In each of Tables3-10, the present elements are listed first followed by the newelements, although this is not a requirement. Therefore, the beginningof each of Tables 3, 5, 7, and 9 are the same as and includes theelements of Table 1, and the beginning of each of Tables 4, 6, 8, and 10are the same as and includes the elements of Table 2.

Present RRLP Measure Position Request and Response Messages

FIG. 4 illustrates Table 1 representing the RRLP position measurerequest message 36 for the present RRLP specification, according to oneaspect of the present invention. FIG. 5 illustrates Table 2 representingthe RRLP position measure response message 37 for a present RRLPspecification, according to one aspect of the present invention.

FIGS. 4 and 5 illustrate the present RRLP measure position request andresponse messages, respectively, as presently described in the RRLPspecification for assisted-GPS (A-GPS), and indicates changes for theintroduction of Galileo into the RRLP specification. The RRLPspecification (TS 44.031) is the main GERAN specification, which needsto be modified in order to support Galileo/GNSS. The RRLP specificationcontains the details of the positioning instructions and assistance dataelements.

The RRLP specification includes a measure position request message,which provides positioning instructions and possibly assistance data tothe mobile station 31, and a measure position response message, whichprovides the mobile station 31 location estimate or pseudo-rangemeasurements from the mobile station 31 to the cellular system 12.

The changes needed for the introduction of Galileo/GNSS are summarizedin the rightmost column of Tables 1 and 2. A blank entry in therightmost column indicates that no change is required. The changes shownin the rightmost column are not specific to any particular option (i.e.,options 1-4), and show which existing A-GPS parameters may be reused ormay need to be replaced, extended or otherwise modified. In some cases,more information on Galileo will be needed (e.g. final specifications)before some parameter changes can be finalized.

In each of Tables 1 and 2, as well as Tables 3 to 10, the number of “>”symbols indicates a hierarchical level of a field within the ASN.1encoding.

Option 1—New Location Method “Galileo”

FIGS. 6 and 7 illustrate Table 3 representing a modified RRLP positionmeasure request message in accordance with option 1, according to oneaspect of the present invention. FIGS. 8 and 9 illustrate Table 4representing a modified RRLP position measure response message inaccordance with option 1, according to one aspect of the presentinvention.

In option 1, new Galileo elements 60 are added to the present RRLPspecification, as shown in Table 1, similar to A-GPS. The present A-GPSspecific information elements continue to be used, and new Galileospecific information elements 60 are added.

The modifications for the RRLP specification are the introduction of newinformation elements in Release 7 extension containers, and aresummarized in Table 3 and 4 for the measure position request message andmeasure position response message, respectively.

Option 1 may be implemented in several ways, and Table 3 and 4 describedone example.

Advantages of Option 1 Include the following:

1. Straightforward evolution of the present RRLP protocol. ExistingA-GPS information elements would still be used for combined GPS-Galileoreceivers. A-GPS-only receiver would continue to use the existing A-GPSinformation elements, and Galileo-only receivers would use only ormostly the new added information elements.

2. Backwards compatibility of existing protocols and A-GPSimplementations are preserved. Existing A-GPS implementations (SMLC andMS) would not be affected by the introduction of Galileo.

3. Conventional and assisted GNSS modes would not require different useralgorithms.

Challenges of Option 1 Include the Following:

1. Assistance data elements are ICD specific. Hence, it may not bepossible to define all required Galileo assistance data elements beforefinal Galileo ICD is available.

2. No generic approach. Every time a new GNSS system has to be added,the specification has to be modified accordingly.

Option 2—New Location Method “GNSS”

FIGS. 10 and 11 illustrate Table 5 representing a modified RRLP positionmeasure request message in accordance with option 2, according to oneaspect of the present invention. FIGS. 12 and 13 illustrate Table 6representing a RRLP position measure response message in accordance withoption 2, according to one aspect of the present invention.

In option 2, a new location method “GNSS” is introduced, and GPS and/orGalileo specific information elements are encapsulated in GNSSinformation elements.

The modifications required for the RRLP specification are theintroduction of new information elements in Release 7 extensioncontainers and are summarized in Table 5 and 6 for the measure positionrequest and measure position response message, respectively.

Option 2 may be implemented in several ways, and Table 5 and 6 describedone example. The example shown in Table 5 and 6 follows a proposal whichassumes that common ASN.1 encoding is possible for GPS and Galileo.

Advantages of Option 2 Include the Following:

1. Option 2 may result in less additional ASN.1 encoding in RRLP for anynew GNSS system provided this is compatible enough with GPS and Galileoto share the same GNSS signaling.

2. Conventional and assisted GNSS modes may not require different useralgorithms.

Challenges of Option 2 Include the Following:

1. Two branches are created in RRLP. Present A-GPS implementations wouldcontinue to use the existing information elements, and futureGPS/Galileo implementations (SMLC and MS) would have to support both theexisting A-GPS information elements and the new GNSS informationelements. If a terminal and a SMLC are GNSS capable, only the new GNSSinformation elements may be used even in case of A-GPS only. However,GNSS capable terminals will still have to support the existing A-GPSinformation elements as well since it cannot be guaranteed that allSMLCs in all networks would support both protocol branches (e.g.,assuming GNSS is added to Release 7, then until all SMLCs supportRelease 7, new Release 7 capable terminals must also support Release 6).

2. A-GPS related information elements are defined twice, in the existingRRLP and in the new GNSS branch.

3. Assistance data elements are ICD specific, but with common ASN.1encoding. Common ASN.1 encoding may not be feasible.

It may be difficult or impossible to add future navigation oraugmentation systems using this option, if these future systems are notcompatible enough with GPS and Galileo. In that case, it might benecessary to revert to a different option (e.g. option 1 or option 4).

Option 3—New Location Method “GNSS” Independent from any ICD

FIG. 14 illustrates Table 7 representing a modified RRLP positionmeasure request message in accordance with option 3, according to oneaspect of the present invention. FIGS. 15 and 16 illustrate Table 8representing a RRLP position measure response message in accordance withoption 3, according to one aspect of the present invention.

Option 3 is similar to option 2 (i.e. a new positioning method “GNSS” isintroduced), but the approach is kept generic in terms of structure aswell as in terms of constellation data. Assistance data elements andmeasurement results will not be specific to any ICD.

Instead of using the satellite navigation data as such or re-using andexpanding the A-GPS concept, the positioning assistance data arespecifically generated for A-GNSS capable terminals. For example, anavigation model will be encoded independent of GPS or Galileo Ephemerisparameters, wherein any orbit model for medium earth orbit (MEO)satellites would suffice. Time is independent of GPS or Galileo time ofweek (TOW), e.g. universal time coordinate (UTC) could be used, etc.

In RRLP, Option 3 would look similar to Option 2; however, there is noneed to explicitly distinguish individual constellations. The differentconstellations still need to be distinguished somehow, since theGPS/Galileo receiver needs to be enabled to measure the GPS and Galileospecific signals. An example is outlined below in Tables 7 and 8. Thedetails of all added elements need to be newly defined and are notreferenced to a particular ICD.

Advantages of Option 3 Include the Following:

1. Generic approach from a protocol point of view. The mobile stationreceiver would see GPS and Galileo constellations as a single GNSS fromthe perspective of receiving assistance data and returning measurements.

2. Assistance data elements are not dependent on a specific ICD. Futuresystems would be supported with minimal or no changes required to thespecification.

Challenges of Option 3 Include the Following:

1. Two branches are created in RRLP. Current A-GPS implementations wouldcontinue to use the existing information elements, and futureGPS-Galileo implementations (SMLC and MS) would have to support both theexisting A-GPS information elements and the new GNSS informationelements. If a terminal and a SMLC are GNSS capable, only the new GNSSinformation elements may be used even in case of A-GPS only. However,GNSS capable terminals will still have to support the existing A-GPSinformation elements, since it cannot be guaranteed that SMLCs innetworks would support both protocol branches (e.g., assuming GNSS isadded to Release 7, then until SMLCs support Release 7, new Release 7capable terminals must also support Release 6).

2. New common orbit models and a new geodetic reference frame may needto be defined to keep this approach truly generic. It may not bepossible to use existing A-GPS user algorithms anymore. New GNSSprotocol would not be compatible with existing A-GPS implementations.

3. Conventional and Assisted GNSS implementations would be different.Different user algorithms for conventional and assisted mode may beneeded. Conventional mode may not be viewed anymore as a special case ofassisted mode.

New Option 4—Adding Galileo Using Existing GPS Units and Formats

FIGS. 17 and 18 illustrate Table 9 representing a RRLP position measurerequest message in accordance with option 4, according to one aspect ofthe present invention. FIGS. 19 and 20 illustrate Table 10 representinga RRLP position measure response message in accordance with option 4,according to one aspect of the present invention.

One of the challenges of options 2 and 3 is the introduction of a newprotocol branch in RRLP, which means that there will be two differentprotocol formats for the support of A-GPS. Therefore, the introductionof Galileo may also have impacts eventually on A-GPS onlyimplementations. On the other hand, Options 2 and 3 try to be genericand introduce the concept of a “Global Navigation Satellite System(GNSS).”

Option 3 has also the advantage that it is independent of a specificICD; and therefore, future satellite systems would be supported withminimal or no changes required to the specification.

Option 4 describes an alternative approach, which combines theadvantages of options 1, 2, and 3, and avoids most of the challengesassociated with options 1, 2, and 3.

In Option 4, Galileo or any other GNSS system is added using theexisting A-GPS information elements. Instead of defining either newGalileo (or other GNSS) specific information elements (e.g., options 1and 2) or new GNSS information elements (e.g., option 3), the existingA-GPS information elements are used also for Galileo satellite vehicles(SV) by introducing new Galileo specific SV-IDs. The existing SV-IDs1-64 are used for GPS satellites only, and additional SV-IDs, e.g. 65-28are reserved for Galileo. Sufficient additional SV-IDs are defined toenable future satellite navigation systems being added easily.

Galileo and envisioned future information elements may be converted tometers, seconds, radians, Hz, etc, which in turn can be converted to theexisting GPS units and formats. The conversion is based on well definedcommon assumptions applied the same way in both the sender and receiverof the information elements. Since the existing GPS information elementparameters have adequate range to cover any comparable satellitesystems, such conversions are possible.

Time dependent assistance data for the new Galileo SV-IDs can either betranslated to GPS time (Option 4a), or can use Galileo time togetherwith conversion parameters GPS to Galileo time offset (GGTO) (Option4b). Either the SMLC (Option 4a) or MS (Option 4b) is performing theconversion to a common GPS time frame. There is no need to introduce a3^(rd) time scale as in Option 3 (e.g., UTC), since any navigation timeframe can be translated to UTC and in turn to GPS time.

Since the existing SV-ID in ASN.1 is not extensible, a new “additionalSV-ID” needs to be defined, covering IDs up to e.g., 255 (or 511 or1023), which allows future GNSSs or augmentation systems to be added.All existing GPS assistance data which are SV dependent are defined inan “Additional Assistance Data” IE applicable for SV-IDs greater than64. The encoding of the “Additional Assistance Data” IE is exactly thesame as the current Assistance Data IEs for GPS. Hence, the impact onexisting protocols and implementations is minimal, but the approach isstill generic.

There may be several possibilities to implement Option 4. The exampleillustrated in Tables 9 and 10 may only be one possibility. Some newASN.1 coding may be avoided by specifying rules for creating RRLPsegments. For example, a new constellation ID parameter (or possibly anSV ID increment) can be included in any RRLP component that containsconstellation specific data. Data for more than one constellation wouldthen not be included in the same RRLP component. This would enablere-use of existing GPS ASN.1 parameters for any constellation, and avoiddefining new ASN.1.

Advantages of Option 4 Include the Following:

1. Generic approach, but still compatible with existing protocol andimplementations. User receiver would see GPS and Galileo constellationsas a single GNSS (from the perspective of receiving assistance data andreturning measurements).

2. Evolution of present protocol. Existing A-GPS information elementswould still be used for combined GPS-Galileo receivers.

3. Backward compatibility of existing protocols and A-GPSimplementations would be preserved. Existing A-GPS implementations wouldnot be affected by the introduction of Galileo.

Alternative Implementations

The system, elements, and/or processes contained herein may beimplemented in hardware, software, or a combination of both, and mayinclude one or more processors. A processor is a device and/or set ofmachine-readable instructions for performing task. A processor may beany device, capable of executing a series of instructions embodying aprocess, including but not limited to a computer, a microprocessor, acontroller, an application specific integrated circuit (ASIC), finitestate machine, digital signal processor (DSP), or some other mechanism.The processor includes any combination of hardware, firmware, and/orsoftware. The processor acts upon stored and/or received information bycomputing, manipulating, analyzing, modifying, converting, ortransmitting information for use by an executable application orprocedure or an information device, and/or by routing the information toan output device.

An executable application comprises machine code or machine readableinstruction for implementing predetermined functions including, forexample, those of an operating system, a software application program,or other information processing system, for example, in response usercommand or input.

An executable procedure is a segment of code (i.e., machine readableinstruction), sub-routine, or other distinct section of code or portionof an executable application for performing one or more particularprocesses, and may include performing operations on received inputparameters (or in response to received input parameters) and providingresulting output parameters.

In various embodiments, hardwired circuitry may be used in combinationwith software instructions to implement the present invention. Thus, thetechniques are not limited to any specific combination of hardwarecircuitry and software, nor to any particular source for theinstructions executed by the data processing system. In addition,throughout this description, various functions and operations aredescribed as being performed by or caused by software code to simplifydescription. However, those skilled in the art will recognize what ismeant by such expressions is that the functions result from execution ofthe code by a processor.

It will be apparent from this description that aspects of the presentinvention may be embodied, at least in part, in software. That is, thetechniques may be carried out in a computer system or other dataprocessing system in response to its processor executing sequences ofinstructions contained in a machine-readable medium.

A machine-readable medium includes any mechanism that provides (i.e.,stores and/or transmits) information in a form accessible by a machine(e.g., a computer, network device, personal digital assistant, computer,data processor, manufacturing tool, any device with a set of one or moreprocessors, etc.). A machine-readable medium can be used to storesoftware and data which, when executed by a data processing system,causes the system to perform various methods of the present invention.Portions of this executable software and/or data may be stored invarious places. For example, a machine-readable medium includesrecordable/non-recordable media (e.g., read only memory (ROM), randomaccess memory (RAM), magnetic disk storage media, optical storage media,flash memory devices, non-volatile memory, cache, remote storage device,etc.), as well as electrical, optical, acoustical or other forms ofpropagated signals (e.g., carrier waves, infrared signals, digitalsignals, etc.), etc. In the foregoing specification, the invention hasbeen described with reference to specific exemplary embodiments thereof.It will be evident that various modifications may be made theretowithout departing from the broader spirit and scope of the invention asset forth in the following claims. The specification and drawings are,accordingly, to be regarded in an illustrative sense rather than arestrictive sense.

1. A communication system comprising: a first global navigationsatellite system (GNSS), adapted to operate according to a firstspecification, and including a first plurality of satellite vehicles(SV), wherein the first plurality of SVs are adapted to be identified bya first plurality of unique corresponding identifications (IDs); and asecond GNSS, different from the first GNSS, adapted to operate accordingto a second specification, different from the first specification, andincluding a second plurality of SVs, different from the first pluralityof SVs, wherein the second plurality of SVs are adapted to be identifiedby a second plurality of unique corresponding identifications (IDs),different from the first plurality of unique corresponding IDs; aprocessor adapted to receive and identify a first plurality ofcorresponding signals transmitted from the first plurality of SVs inresponse to the first plurality of unique corresponding IDs, adapted toreceive and identify a second plurality of corresponding signalstransmitted from the second plurality of SVs in response to the secondplurality of unique corresponding IDs, and adapted to determine positionlocation information in response to receiving and identifying the firstplurality of corresponding signals and the second plurality ofcorresponding signals.
 2. A communication system, according to claim 1,further comprising: a mobile station adapted to communicate with theprocessor and adapted to identify a position of the mobile station inresponse to receiving the position location information.
 3. Acommunication system, according to claim 2, wherein the processor islocated in at least one of the mobile station and a location server. 4.A communication system, according to claim 3, further comprising: ameasure position request message transmitted from the location server tothe mobile station.
 5. A communication system, according to claim 4,wherein the measure position request message, further comprises: firstinformation representing positioning methods for the first GNSS; andsecond information representing positioning methods for the second GNSSand corresponding to the positioning methods for the first GNSS.
 6. Acommunication system, according to claim 5, wherein the measure positionrequest message, further comprises: first information representingassistance data for the first GNSS; and second information representingassistance data for the second GNSS and corresponding to the assistancedata for the first GNSS.
 7. A communication system according to claim 6,wherein each of the first information representing assistance data forthe first GNSS and the second information representing assistance datafor the second GNSS, further comprises one or more of the followingelements: differential corrections, navigation model, almanac,acquisition assistance, and real-time integrity.
 8. A communicationsystem according to claim 2, further comprising: a measure positionresponse message transmitted from the mobile station to the locationserver.
 9. A communication system according to claim 8, wherein themeasure position response message, further comprises: first informationrepresenting measurement information for the first GNSS; and secondinformation representing measurement information for the second GNSS andcorresponding to the measurement information for the first GNSS.
 10. Acommunication system according to claim 9, wherein each of the firstinformation representing measurement information for the first GNSS andthe second information representing measurement information for thesecond GNSS, further comprise one or more of the following elements: aframe number, global positioning satellite (GPS) time of week (TOW), andmeasurement parameters.
 11. A communication system according to claim10, wherein the measurement parameters further comprise one or more ofthe following elements: an SV ID, C/N_(o), Doppler, whole chips,fractional chips, a multi-path indicator, and a RMS pseudo-range error.12. A communication system according to claim 1, wherein the first GNSSand the second GNSS further comprise: a global position satellite (GPS)system and a Galileo satellite system, respectively.
 13. A communicationsystem according to claim 1, wherein the first plurality ofcorresponding signals and the second plurality of corresponding signalseach further comprise: time dependent assistance data, wherein the timedependent assistance data for the second plurality of correspondingsignals are adapted to be translated to the time dependent assistancedata for the first plurality of corresponding signals.
 14. Acommunication system according to claim 1, wherein the first pluralityof corresponding signals and the second plurality of correspondingsignals each further comprise: time dependent assistance data, whereinthe time dependent assistance data for the second plurality ofcorresponding signals are combined with an offset representing aconversion from the time dependent assistance data for the firstplurality of corresponding signals to the time dependent assistance datafor the second plurality of corresponding signals.
 15. An apparatuscomprising: a processor adapted to: receive and identify a firstplurality of corresponding signals transmitted from a first plurality ofsatellite vehicles (SV), associated with a first navigation satellitesystem (NSS) adapted to operate according to a first specification, inresponse to a first plurality of unique corresponding IDs, associatedwith the first plurality of SVs, receive and identify a second pluralityof corresponding signals transmitted from the second plurality of SVs),associated with a second navigation NSS adapted to operate according toa second specification, in response to the second plurality of uniquecorresponding IDs, associated with the second plurality of SVs, anddetermine position location information in response to receiving andidentifying the first plurality of corresponding signals and the secondplurality of corresponding signals.
 16. An apparatus, according to claim15, wherein the processor is located in at least one of a mobile stationand a location server.
 17. An apparatus, according to claim 16, furthercomprising: a measure position request message transmitted from thelocation server to the mobile station.
 18. An apparatus, according toclaim 17, wherein the measure position request message, furthercomprises: first information representing positioning methods for thefirst NSS; and second information representing positioning methods forthe second NSS and corresponding to the positioning methods for thefirst NSS.
 19. An apparatus, according to claim 17, wherein the measureposition request message, further comprises: first informationrepresenting assistance data for the first NSS; and second informationrepresenting assistance data for the second NSS and corresponding to theassistance data for the first NSS.
 20. An apparatus according to claim19, wherein each of the first information representing assistance datafor the first NSS and the second information representing assistancedata for the second NSS, further comprises one or more of the followingelements: differential corrections, navigation model, almanac,acquisition assistance, and real-time integrity.
 21. An apparatusaccording to claim 16, further comprising: a measure position responsemessage transmitted from the mobile station to the location server. 22.An apparatus according to claim 21, wherein the measure positionresponse message, further comprises: first information representingmeasurement information for the first NSS; and second informationrepresenting measurement information for the second NSS andcorresponding to the measurement information for the first NSS.
 23. Anapparatus according to claim 22, wherein each of the first informationrepresenting measurement information for the first NSS and the secondinformation representing measurement information for the second NSS,further comprise one or more of the following elements: a frame number,global positioning satellite (GPS) time of week (TOW), and measurementparameters.
 24. An apparatus according to claim 23, wherein themeasurement parameters further comprise one or more of the followingelements: an SV ID, C/N_(o), Doppler, whole chips, fractional chips, amulti-path indicator, and a RMS pseudo-range error.
 25. An apparatusaccording to claim 15, wherein the first NSS and the second NSS furthercomprise: a global position satellite (GPS) system and a Galileosatellite system, respectively.
 26. An apparatus according to claim 15,wherein the first plurality of corresponding signals and the secondplurality of corresponding signals each further comprise: time dependentassistance data, wherein the time dependent assistance data for thesecond plurality of corresponding signals are adapted to be translatedto the time dependent assistance data for the first plurality ofcorresponding signals.
 27. An apparatus according to claim 15, whereinthe first plurality of corresponding signals and the second plurality ofcorresponding signals each further comprise: time dependent assistancedata, wherein the time dependent assistance data for the secondplurality of corresponding signals are combined with an offsetrepresenting a conversion from the time dependent assistance data forthe first plurality of corresponding signals to the time dependentassistance data for the second plurality of corresponding signals.
 28. Amethod comprising: receiving and identifying a first plurality ofcorresponding signals transmitted from a first plurality of satellitevehicles (SV), associated with a first navigation satellite system (NSS)adapted to operate according to a first specification, in response to afirst plurality of unique corresponding IDs, associated with the firstplurality of SVs, receiving and identifying a second plurality ofcorresponding signals transmitted from the second plurality of SVs),associated with a second navigation NSS adapted to operate according toa second specification, in response to the second plurality of uniquecorresponding IDs, associated with the second plurality of SVs, anddetermining position location information in response to receiving andidentifying the first plurality of corresponding signals and the secondplurality of corresponding signals.
 29. A signal interface protocol,communicated between a location server and a mobile station in acommunication system, comprising: a measure position request message,transmitted from the location server to the mobile station, furthercomprising: first method information representing positioning methodsfor a first navigation satellite system (NSS); second method informationrepresenting positioning methods for a second NSS and corresponding tothe positioning methods for the first NSS; first assistance informationrepresenting assistance data for the first NSS; and second assistanceinformation representing assistance data for the second NSS andcorresponding to the assistance data for the first NSS.
 30. A signalinterface protocol, according to claim 29, further comprising: a measureposition response message, transmitted from the mobile station to thelocation server, further comprising: first measurement informationrepresenting measurement information for the first NSS; and secondmeasurement information representing measurement information for thesecond NSS and corresponding to the measurement information for thefirst NSS.
 31. A signal interface protocol, according to claim 29,wherein each of the first assistance information representing assistancedata for the first NSS and the second assistance informationrepresenting assistance data for the second NSS, further comprises oneor more of the following elements: differential corrections, navigationmodel, almanac, acquisition assistance, and real-time integrity.
 32. Asignal interface protocol, according to claim 30, wherein each of thefirst measurement information representing measurement information forthe first NSS and the second measurement information representingmeasurement information for the second NSS, further comprise one or moreof the following elements: a frame number, global positioning satellite(GPS) time of week (TOW), and measurement parameters.
 33. A signalinterface protocol, according to claim 32, wherein the measurementparameters further comprise one or more of the following elements: an SVID, C/N_(o), Doppler, whole chips, fractional chips, a multi-pathindicator, and a RMS pseudo-range error.
 34. A signal interfaceprotocol, according to claim 29, wherein the first NSS and the secondNSS further comprise: a global position satellite (GPS) system and aGalileo satellite system, respectively.
 35. A signal interface protocol,according to claim 29, further comprising: a time offset representing aconversion from time dependent assistance data for the first NSS to timedependent assistance data for the second NSS.
 36. A signal interfaceprotocol, communicated between a location server and a mobile station ina communication system, comprising: a measure position response message,transmitted from the mobile station to the location server, furthercomprising: first measurement information representing measurementinformation for the first NSS; and second measurement informationrepresenting measurement information for the second NSS andcorresponding to the measurement information for the first NSS.
 37. Asignal interface protocol, according to claim 36, further comprising: ameasure position request message, transmitted from the location serverto the mobile station, further comprising: first method informationrepresenting positioning methods for a first navigation satellite system(NSS); second method information representing positioning methods for asecond NSS and corresponding to the positioning methods for the firstNSS; first assistance information representing assistance data for thefirst NSS; and second assistance information representing assistancedata for the second NSS and corresponding to the assistance data for thefirst NSS.